1. Field of the Invention
The present invention relates to call set-up techniques, hardware and software interfaces and methods of operating same, for the transmission of mixed-media data across telecommunications networks. More particularly, although not exclusively, the present invention relates to techniques for setting up calls consisting of voice and video data, across telecommunications networks, and a hardware and software interface and method of operating same.
2. Description of the Related Art
Devices such as videophones, video conferencing systems and mixed media data transmission/communication systems are known in the art. Depending on the particular application and the quality of service that is needed, the combined transmission of mixed media, for example, voice and video, can require bandwidth at the limit of or exceeding that which is currently available.
Solutions to this problem have generally focused on hardware-based solutions. The reader is referred to U.S. Pat. No. 5,543,939 (to Harvey et al) and U.S. Pat. No. 5,371,534 (to Dagdeviren et al) in this regard.
A problem with hardware-based approaches is that the existing telecommunication infrastructure often needs to be physically supplemented or modified, for example by augmenting or replacing existing copper landline with fibre optics.
Although such solutions may be physically practical, they may be economically prohibitive.
It is therefore desirable to implement a mixed media, particularly audio/video, data transmission solution which does not require significant modification of the communications infrastructure itself.
Audio-visual communication introduces issues of privacy and presentation as well as the ability to communicate visual cues. To gain widespread acceptance, videophone services will need to address these issues by incorporating controls and procedures particular adapted for dealing with video/audio communication.
It is accordingly one object of the invention to provide a method and apparatus for setting up and handling mixed-media calls which allows the transmission of mixed media data, preferably using substantially existing network infrastructures, that is relatively straightforward to implement. It is a further object of the invention to provide a videophone interface and a method of operating same which addresses at least some of the human factors issues relevant to combined video and audio communication.
For the purposes of describing the following preferred embodiments of the invention, following description will be given in the context of the Groupe Special Mobile (GSM) model. However, this is not to be construed as a limiting application. Other networks may be amenable to operation in accordance with the invention.